I have the same set up on my MGBs and once had a similar problem.
Turned out that a large portion of the flange on the distributor casting
that the clamp "clamps" to had broken away and there was nothing to
clamp to!

This may be your problem, and the only fix is to replace the
distributor.

Kevin Hayden wrote:
>
> After it ran for about a minute or so, the distributor popped out about
> 1/4" again and the Vanagon died!  I went back and looked---I was able to
> spin the rotor by hand again!!
>
> Could it possibly be that it's a bad clamp??  It's torqued all the way,
> but I noticed there is a small gap in the clamp near the distributor
> shaft.  The nut and bolt assembly seem to be bent a bit in an arch.  I
> don't want to mess with it until I get your opinions on it--I don't want
> to do any damage to Roxanne (the poor thing needed a name)...Don't turn
> on the 'Red Light' is my prayer each time I get in to drive it!!  I
> don't want to take this on the road to cause any further injury to her
> or my sanity!! :-)  She really likes the tow trucks--she's a spoiled
> brat!!!!!! :-)
>
> By the way, if it's not the clamp what else could possibly be causing
> the distributor to pop out?
>
> Thanks Again for all your help, and I look forward to all your
> suggestions, comment and help!!  I have tomorrow off so I can spend all
> day putting to work all your suggestions!!!
>
> Kevin From Coal Country, PA
> sevenkevin@webtv.net

--
Stuart MacMillan
Seattle

'84 Vanagon Westfalia w/2.1
'65 MGB (Daily driver since 1969)
'74 MGB GT (Restoring sloooowly)

Personal mechanic for:
'70 MGB GT (Daughter's)

Assisting on Restoration (and spending OPM):
'72 MGB GT (Was daughter's, now son's)
'64 MGB (Son's)

Stripped and gone but their parts live on:
'68 MGB, '73 MGB, '67 MGB GT